Hydrocarbon reconstruction



Patented July 1946 UNITED STATI-:sf PATENT OFFICE; f

HYDROCARBON RECONSTRUCTION Frederick E. Frey, Bartlesville, Okla., vassigner to Phillips Petroleum Company, a corporationof Delaware Application January 13, v1942, Serial No. 426,627

vThis invention relates to the conversion of hyvdrocarbons. chemical reconstruction of hydrocarbons-in the presence of hydrofluoric acid as a catalyst. This application is a continuation in part of my copending application Serial No. 323,443, filed March 11, 1940, now Patent 2,317,901, issued April 27, 1943.

I have discovered that, in the presence of `substantial proportions of khydroiluoric acid andv under suitable conditions of time and/or'temper- Iature, hydrocarbons cany be catalytically reconstructed to hydrocarbons of differentA lcarbonvskeleton arrangement and/or., different vboiling point, thereby effecting an improvement in yproperties and in usefulness for specific purposes. Parainic hydrocarbons boiling in the motorfuel range, for example, undergo conversioni-,o isomers and to hydrocarbons of both lower and higher molecular weights and correspondingly lower and higher boiling temperatures. Similarly, motor-fuel fractions containing minor proportions of unsaturates are converted into completely saturated materials containing some lower-and higher-boiling products. Accordingly, the present invention comprises subjecting hydrocarbon material consistingk predominantly of saturated hydrocarbons to the action of a substantial'provportion ofconcentratedhydrofluoric'acid at a hydrocarbons by reaction with unsaturated hy,-

drocarbons. The specific effect-produced in any particular case is usually one or more of the following: (1)' increased octane number of motorfuel range hydrocarbon materials; (2)V enhanced susceptibility to antiknock improvement by the addition of tetraethyl lead to hydrocarbon materials; k(3) conversion of hydrocarbons to hydrocarbons of higher and/or lower molecular weights; (4) decreased content of unsaturates in hydrocarbon materials; (5) conversion of hydrocarbons to relatively highly branched isomerio More particularly, Y ity relates fto' 18 Claims.v (Cl. 260-683.5)

compounds; (6) conversion of noncyclic hydrocarbons to cyclic compounds. When the initial material has a considerable proportion of naphthenes,disproportionationofV these to paraflins and aromatics appears to occur, especially at relatively drastic conditions oi 'time and 'temperature. y The production of these effects indicates that several different types of Vchemical reactions may beiin'volved vin-the present 'process'.ffor; reconv Y The `predominating t U reaction types, as deduced `from 'a consideration struction of hydrocarbons.

of reactants, products, operating conditions,fand theoretical aspects relating to the invention, may be exemplified as follows: Y Y

, 0 y (heptanes) Y (hexanes) '(octanes) y HF (2) (a) n-heptane 1 branched heptanes j ,HF Y y(b) 1-butano Isobutane Y HF (3) 2C1H1 06H12 l 2041110 (heptanevs) (cyclohexane) (butanes) H (4) 06H12 t CHaCtHa (cyclohexane) (methyl cyclopentane) The rst two reactions, namely, reconstruction to produce both higher-and lower-boiling parafns,

'and isomerization, respectively, predominate under relatively mild treating conditions. "The yields of cyclics, exemplified' in thethird equation by cyclohexane, is increased by increasing theV temperature and/or the timeofu reaction. A

vfourth ytype. of reaction' is believed to account for the increase in saturation and stability that occurs when motor fuel comprising some unsaturated material is treated. By this reaction, olens arey converted to cycloparains such as cycloheXane and its derivatives. This reaction may be exemplied as follows: l

" C eHuC Ha (methyl cyclohexane) (heptylene) Several other types of reactions undoubtedly occur in the reconstruction process; however, the above-mentioned kve types appear to accountl for most of the effects which are produced. The general term reconstruction is used herein to denoteV the production of one or more of the abovementioned effects and/or of other inherent advantageous effects which result from the practice of my invention.

Insofar as I have been able to determine, .the actual catalyst which promotes the reconstruction reaction, or reactions, is concentrated hydrouoric acid. Other materials may be present which will exert a slight promoting effect, such as compounds fortuitously formed in minor amounts by reaction of hydrouoric acid with Walls of reaction vessels, but the presence of such compounds does not alter the fact that hydrofluoric acid is the catalyst. Agents which promote the action of the hydrofluoric acid may be added in many instances without changing the character of the reaction nor exceeding the scope of the spirit of the invention and of the disclosure. The reaction may take place in the presence of relatively or essentially inert solids of large surface area such as activated charcoal, bauxite, etc. which will tend to adsorb and concentrate hydrofluoric acid in an active state.

When it is desired to maintain hydrouoric acid in a liquid phase at higher reaction temperatures, this effect may be aided by incorporating with the hydrofluoric acid inorganic salts which are soluble in hydroluoric acid, especially the iiuorides of alkaline materials and of alkali-earth metals. i

' An object of this invention is to provide a new process for catalytically reconstructing hydrocarbon material.

lA further object is to produce hydrocarbons of -loWer and/or higher molecular weight and of correspondingly lower and/or higher boiling points than those of the material treated.

A specific object is to treat motor fuel so as to enhance its susceptibility to improvement of its antiknock rating by the addition of tetraethyl lead.

Another speciiic object is the production of saturated hydrocarbons boiling in the motor-fuel range and having increased unleaded and leaded octane numbers as compared with the original material or corresponding fractions thereof.

Another specific object is to improve hydrocarbons, such as those obtained by petroleum renery operations, and especially those boiling in the motor-fuel range, by increasing the degree of saturation and, consequently, the stability, when a small but undesirable proportion of unsaturates are originally present.

Another specific object is to convert normal or slightly branched aliphatic hydrocarbons to more highly branched aliphatic hydrocarbons.

A further object is to convert normal paraffins into corresponding isoparafns.

Other objects and advantages of my invention will be apparent from the accompanying disclosure and discussion.

An understanding of some of the many aspects of the invention may be aided by the accompanying drawing, which is a flow-diagram illustrating a preferred arrangement for practicing the invention.

A suitable hydrocarbon material, admitted tov The proportion of hydroluoric acid is preferablyy in the range from 0.2 to l times by weight of the total l hydrocarbon fluids. Proportions much smaller than this are sometimes insuiiicient to effect the desired degree of conversion, whereas much larger proportions vdecrease undesirably the 4 production capacity of equipment of any given size; however, proportions outside of the preferred range should not be excluded from the scope of this invention. Mixing of the hydrofluoric acid and the hydrocarbon material may be effected by any of a number of methods, as by the use of a special mixer or emulsier, or by maintaining high linear velocities in conduit I3; devices such as sharp bendsI or constrictions in conduit I3 are advantageous in some instances.

The resulting mixture is passed to heater I?, wherein it is heated to a suitable reaction temperature. Heater I1 preferably consists of a tube cOil surrounded by hot gases or liquids. In some instances, as When the desired reaction temperature is atmospheric, or only slightly above, heater I'I is unnecessary and may be oy-passed or. removed from the system.

Depending somewhat .upon the character of the initial hydrocarbon material, the reaction tenu perature may vary from about 50 to about 1090o F.; a temperature in the range of 250 to 800D F. is

usually preferred. The pressure may vary from about atmospheric to 5000 pounds per square inch, or more. The reaction time may vary from about one minute to twenty hours or more, high values applying to relatively low reaction temperatures or to highly refractory reactants, and low values applying to relatively high operating temperatures or to highly reactive reactants. Depending upon the particular hydrocarbon material being treated and upon the region of temperature and pressure under which the reconstructing reaction is conducted, the mixture of hydrocarbons and catalyst may be in a wholly gaseous phase, in a partially liqueed condition, or in a Virtually wholly condensed condition. The extent of conversion increases with increase in temperature, time, and/or catalyst concentration. Changes in pressure appear to affect the nature of the reaction appreciably, particularly at high temperatures. In general, an increase in pressure retards the formationof lower-boiling hydrocar- 4bons and increases the formation of higher-boilinghydrocarbons; also, increase in pressure tends to increase the rate of conversion, particularly under gas-phase operating conditions. Over-reacting may lead to the formation of some heavy oils, usually of relatively low value, and of some organic iiuorine-containing compounds of high molecular weight, which usually remain mostly dissolved in the hydrouoric acid when the proportion of acid is large enough for a separate liquid acid phase to be produced upon cooling the reaction mixture.

The optimum operating conditions in any specific case are dependent upon the nature of the feed material aswell as upon the extent of reconstruction desired. For example, in treating a lube oil to decrease unsaturation or to modify such properties as the pour point, the viscosity, or the like, relatively mild reconstructing conditions are used. By contrast, in reconstructing relatively refractory materials, such as normal butane or normal pentane, to produce isomers and higher-and/or lower-boiling hydrocarbons, relatively drastic conditions are required. For reconstructing normal butane to produce isobutanc, the preferred conditions are a temperature in the range of 400 to 800 F., a pressure in the range of 250 to 2500 pounds per square inch, and a reaction time in the range of 1 to 100 minutes; but

` conditions outside of these ranges may at times used, in accordance with the principles of the invention. The reconstructing reactions to improve the rantikno'ck"characteristics of' motorffuel hydrocarbons are usually carried-out under somewhat less drastic conditions than those preferred for the reconstruction of normal butane. For any rparticular case, the optimum;k conditions are readily determinableby trial "by one skilled in the art in the light ofthe present disclosure and discussion. f

When the requisitereaction time is relatively short, such as about one to about ten minutes, the reaction may be carried out preferably wholly in tu-be heater I1, from which the reaction mixture is conducted via pipe I8 and vvalve I9 directly to cooler and 'separator 20. -When the requisite re`- action time is relatively long, it is advantageous to pass the heated, mixture from heater rI'l through valve 2| and conduit 22A to reactor 23, wherein the mixture isdigested at the reaction temperature and pressure for a time sufficient to effect the desired conversion. Such digestion may need AtoA be accompanied by vigorous agitation when relatively immiscible liquid phases are present. When liquid-phase or mixedfpha'seroperating conditionsl are used, means for effecting agitation or miXingrin reactor 23 are usually desirable, Y because liquid hydrocarbon-hydrofluoric acid'mixtures tend to separate into two layers. Mixing may be effected by any well-known means, such as mechanical stirrers, relatively constricted orifices or zones` through which the mixture is passed at high linear velocity, or the like; it may be aided by recirculation, las through circuit 24, pump 25, and valves 26 and 21. If all components of the reaction mixture are in a single phase, no means of agitation willgenerally be required. Usually the heat of reaction is relatively small and does not markedly affect the temperature of the reacting mixture. Preferably, reactor 23 is ,operated adiabatically; but, if desired, auxiliary heating or cooling devices may be incorporated in reactor '23,. although control of the temperature therein is more suitably effected by controlling the heat input in heater l1.

YI have found that the solubility of saturated hydrocarbons in hydrogen fluoride, and the solubility of hydrogen uoride in 'such hydrocarbons increases with elevation in temperature. At temperatures near but below the critical for hydrogen fluoride, under supercritical pressures Ihave found it convenient to operate with a liquid hydrogen iluoride phase containing a high content vof dissolved hydrocarbon. rIn such instances ag1- tating means are sometimes unnecessary, during the digestion period in which the reaction is ef` fected, a's discussed. Similarly, I may operate in the sub-critica1 temperature region with respect to a hydrocarbon phase carrying in solution a high proportion pf hydrogen fluoride or acid. Reaction may be effected in acid rich liquid phase by contacting the hydrocarbon to be converted with liquid hydrogen fluoride at elevated temperature, thereafter separating the acid phase, now containing the reactant hydrocarbon in solution, and then subjecting the solution to reaction conditions. The acid rich effluent from such a step may be distilled to recover the volatilizable hydrocarbons together with a part of the acid, While the residue of hydrocarbon-depleted acid may be used again in the conversion Step. In another modication hydrocarbon material may be i'acid phase, wherein most of the reaction takes place;V Converted hydrocarbonseparates as 'an l Vthrough conduit 28 havingvalve 29 to separator 20 Ywherein it is separated into two liquidphases,

as lby cooling and gravitation or centrifugal means. The lighter' 'or hydrocarbon phase is passed vthrough conduit 30 Vhaving valve 3| to fractionator32. The heavier or hydrofluoricacid phase may be recycled via conduit`33 having valve 34 to pump I5; however, preferably at least part of it is passed through valve 35 and conduit 36'to acid fractionator 31, wherein it is puriedbefore being reused.

From -fractionator 32 is passed a comparatively minor overhead fraction, which comprises free hydrogen fluoride and relatively low-boiling hydrocarbons, through valve 38 and conduit 39 to separator 4ll.V The rremaining or major portion of material, which comprises substantially pure hydrocarbons with very small proportions of organic fluorine compounds, is passed through valve 4| and conduit 42 to deuorinator or i'luorine remover 43.

` Fluoriner remover 43 comprises a chamber containing a contact mass having hydrogenation and/ or dehydrogenation properties, such as bauxite, alumina, or other similar material. Usually suitable operating conditions are a temperature in the range of 75to 250 F. and a space velocity Yin the range of 1 to 50 volumes of liquid hy.- drocarbon material per volume of contact mass per hour. Under such conditions, which may. be particularly selected in accordance with a trial, organically combined uorine is substantially completely removed from the hydrocarbon material, which then is `passed through valve 44 4and conduit 45 to fractionator 46. Such defluorination'is more completely disclosed, and is claimed, in my copending application Serial No. 398,361, filed June 16, 1941. This is now Patent 2,347,945, issued May 2, 1944. When organic fluorine compounds are not present or harmful, ory

are to be removed by treating only a part of the material present, the hydrocarbon material can 'be passed directly to fractionator 46, entirely or vin,pa.r1'.,firom conduit 42 through conduit 69 and the principal product is motorfueljthe follow- .introduced into the lower end of a column'of y liquid acid maintained at reaction temperature through which the hydrocarbon ascends by virtue of its lower density, undergoing as it ascends -partitionwith the hydrocarbon dissolved in the ing four fractions may be obtained: (l) a byproduct fraction comprising chiefly isoparains boiling below the motor-fuel range, whichis withdrawn through outlet 4l having valve 48, and which may be used as conversion stock in an alkylation process; (2) a motor-fuel fraction, which is withdrawnthrough outlet 49 having valve 50; (3) a fraction vboiling above the motorfuelrange, which may be recycled by way of valve 5I and conduit 52 to pump Il; and (4) a bottom fraction comprising a high-boiling hydrocarbon residue, which may be Withdrawn through outlet 53 having valve 54. If desired, the motor-fuel fraction withdrawn may be limited to a relatively narrow-boiling range in order to obtain relatively concentrated specific materials, such as, for example, highly-branched octanes, whileother hyvseparately-recovered, by means *not shown or through 53, and/or passed tothe conversion zone through' conduit 52.

The overhead effluent from fractionator 32'is separated into two phases in separator 40, as by cooling and centrifugal or gravitational means. The lighter or hydrocarbon phase is withdrawn through outlet 55 having valve VV55; and the heavier or hydroiiuoric acid phase is recycled through conduit 1l and valve 51 to conduit 33 and to pump I5. f Part or all of the light hydrocarbon material passed through conduit 55 may be returned to fractionato-r 32 through conduit 61 controlled by valveI 58 in which case light hydrocarbons mayv be completely discharged through conduity 41. fully disclosed, and is claimed, inmy copending application Serial No. 315,063, Filed March 11, 1940, now Patent 2,322,800, issued June 29, 1943.

Fractionator 31 separates the acid eiiiuent from separator 20 into an overhead fraction comprising anhydrous hydrogen fluoride and small proportions of hydrocarbons, which is passed by way of valve 58 and conduit 50 to separator 60, and into a bottom or sludge fraction comprising fluoro-organic material, tar, etc., which is withdrawn through outlet 5! having valve 52.

In separator 60, the overhead effluent from acid fractionator 31 is separated into two phases las by cooling and centrifugal or gravitational means; a hydrocarbon phase which is withdrawn through outlet 63 havingvalve 04, and a concentrated hydroiiuoric acid phase which is recycled by way of va1ve55 and conduit `(it to pump I5. Any hydrocarbon phase may, if desired, be passed from conduit 63 through conduit rl2 and valve 'F3 to conduit I8 and separator 20.

If desired, the sludge formed at the bottom of fractionator 31 may be subjected to thermal decomposition, whereby free hydrogen fluoride is liberated, and the resulting recovered hydrogen fluoride may be recycled to pump I5. The thermal decomposition may be effected in fractionator 31 itself, if a-suitably high bottom temperature is emp1oyed,ror it may be effected in a separate means, not shown.

The process of this invention is applicable to many different specific hydrocarbon feed materials, and it may be employed to produce several desirable effects. For example, in the production of isoparaffins of five toten carbon atoms per molecule, suitable for use in aviation gasoline, fractions of straight-run gasoline or natural gasoline are suitable; these fractions may be obtained by many known means, such as fractional distillation, selective extraction, and the like. lsopentane, when reconstructed by hydrogen `fluoride, yields, besides some isobutane, considerable amounts of `hexanes and heptanes, mainly of rather highly branched structure, that are suitable for inclusion in aviation fuel.

A few of the many aspects of my invention are illustrated in the following examples, which are purely illustrative and not necessarily limitative of the invention.

Example I A fraction fromV natural gasoline that boiled in the methylhexane range was found to have a clear ASTM octane number of 46.9 and a lead susceptibility of 11.7 octane numbers for 1 cc. of tetraethyl lead per gallon. A portion of this material was agitated with one third of its volumne of concentrated hydrogen fluoride for 26 hours at an average temperature of 270 F. anf under pressure sucient to maintain all components of Such an operation is more thereaction mixture in th'efliquid phase. The reaction mixture was then cooled to 32 F. and was allowed to stand for a few minutes, Whereupon two liquid phases separated out. The upper or hydrocarbon phase was equivalent to93 per cent by weight ofA theV Aoriginal hydrocarbon charge. 'I'hishydrocarbon product'was found to have approximately the following composition, in per cent by weight: propane, 1,2; isobutane, 4.1; pentane, 2.3;v hexanes, 1.2; highly branched heptanes, 18.4; hydrocarbons boiling in the range of 93.5 to 100 C., 43.0, which appeared to be composed of normal heptane, isooctane, and cyclics; hydrocarbons boiling above 100 C., 11.4. This product was found to havev an ASTM- octane number of 54.6 and a lead susceptibility of 12.5; it contained virtually no olenic unsaturation (by bromine titration).

Material of thefcharacter produced in this'example is suitable for blending in ordinary motor fuel.. Preferably, however, an aviation-gasoline cut, such as an isooctane fraction, is separated out, and part of the remainder is recycled to the treatment withvhydrogen uoride, and/or, 'optionally, part is used for conversion stock in other hydrocarbon-conversion processes. For example, the isobutane fraction is particularly advantageous for use in alkylation processes; thefractions boiling above the aviation-gasoline range are suitable for cracking stock to produce cracked gasoline; and the relatively low-octane fractions boiling within the gasoline range are suitable for recycling to my process.

Example II A substantially pure isooctane fraction was agitated for one hour at a temperature of F. with an equal volume of concentrated hydrofluoric acid. The reaction mixture was Withdrawn and was separated, by settling and decanting, into an acid phase and a hydrocarbon phase. The hydrocarbon phase wasequivalent by Weight to 94.1 per cent of the original hydrocarbon charge. It had the following composition in mol per cent; isobutane, 29.2'; Pentanes, 9.1;'hexanes 4.8; heptanes, 4.5; hydrocarbons boiling higher than heptanes, 52.4. The composition of the normally liquid portion of the product, in per cent by weight, was as follows: pentanes and h'exanes, 15.5; hep-k tanes, 6.8; octanes, 34.2; nonanes, 9.3;` decanes, 10.9; undecanes and dodecanes, 15.0; hydrocarbons boiling higher than dodecanes, ,8.3.

This example illustrates the formation of hydrocarbons having higher and lower boiling points and correspondingly higher and lower molecular weights than those of the original material. The lower boiling compounds, particularly isobutane, are suitable for conversion stocks in alkylation processes for producing aviation gasoline; the higher-boiling compounds, such as undecanes and higher, may be advantageously recycled within my process, or they may be used, for examplaas conversion stock in cracking processes to produce aviation gasoline. The middle-range hydrocarbon material, such'as pentanes t0 decanes, inclusive, is suitable for use as aviation motor fuel.

Example III In a process for'manufacturing-aviation gasoline, a by-product motor-fuel-range hydrocarbon mixture is produced that has an octane number of about 63 and a tetraethyllead response of '7.5 octane numbers for 1 cc. of tetraethyl lead per gallon. This material is treated, in accordance with the principles of my invention, with an equal volume of concentrated hydrofluoric acid. The

conditions are: temperature 350 F.; pressure,

equivalent to the vapor pressure of the reaction mixture; time, 40 minutes; and rapid agitation. The reaction mixture isV partly in the vapor, phase. On being cooled, as to about V40 to 80 F., theresulting Ymixture is separated into two ,liquidV phases. From the hydrocarbon' phase, which is` equivalent by weight to about 86 percent of ythe* original charge, is separated an aviation-gasoline f fraction having an octane number of 85 and a lead lresponse of 12.5. e A relatively low-boiling fraction comprising mostly isobutane is used as feed to an alkylation process for producing aviation gasoline, and a relatively high-boiling fraction is subjected to a cracking process for produca A small proportion of .l

ing cracked gasoline. Y tarry residue is withdrawn fromthe system.

Elample IV shaken 4continuously by a Ymechanical rocker.,

The reaction mixture was then withdrawn, and a hydrocarbon phase was recovered by decanting.`

It V was found by fractional analysis to have the followingl composition in per cent by liquid volume. .Y Y.

- Lower-boiling v Tracel inch. After 3 hours th'e heatv was turnedroi, and

the bomb was rapidly cooled.y The products were wtihdrawn and separated by decantation. The

recovered hydrocarbon layer weighed 20.3 grams; it was treated with alkaline solution to'remo've.

hydrogen fluoride. The resulting hydrocarbon product was found by fractional analysis to have the following composition, in per cent by weight:

`Propane 3.2 Isobutane 4.3 Normal butane 90.0 Isopentane 2.5

Ezramplel V Inan experiment similar to that of `Example IV, 64y grams'of C. P." normal butane and 188 Methane 0.6 Propane 10.1 v Isobutane T 25.9 Norma1 butano 50.8 Isopentane 8.1 Norma1pentane 2.0 Hexanes 2.0 Heptanes 0.5

The fextent of isomerization of normal butane to isobutane was considerably more than that obtained in Example IV, as was also the conversion to isopentane and lhigher-boiling parans.

v 'Approximately equal proportions by volumeof` isopentane andv yanhydrous hydrogen fluoride were charged to a steel bomb. For a period of 28 daysl the boint'v was maintained 'at atemperaturef of 175 F. by'v an electric heating coil andwas Butanes 8.5 Isopentane 70.2 N-.Pentane 8.3 Hexanes 12.4 High bniling 0.6

Example VII Toa steel bomb of 400 cc. capacity were charged 84 grams of anhydrous hydrouoric acid and43 grams of C. P. normal pentane. The'bomb was heated to` 572 F. and was maintained at that temperature for A30 minutes. vIt was then cooled, and the products were withdrawn. It was found by fractional'analysis that approximately 10l per centofiv the normal pentane had reacted to give the following products in the proportions shown:

Mol

' Product: Y percent Lower boiling .'Irace Propane I 17.3

Isobutane 31.5

Normal lontane 19.7

Isopentane 22.5"

Hexane 6.0

Higher-boiling 3.0

n 100.0 Example VIII To a steel bomb were charged 92.4 grams of concentratedhydroiluoric acidand 50.6 grams of normal pentane. The bomb was surrounded byV an electrical heating jacket, and was heated to 570 F. in 70 minutes, as follows: up to 356 F, in 30 minutes, from 356 to 453 F. in 17 minutes, and from 453 to 570 F. in 23 minutes. At 570 F. a pressure gage attached to the bomb registered 4,240 pounds per square inch. The bomb was maintained at this temperature for 4 hours; and was then cooled to 212 F. in 14 minutes. 'I'he hydrocarbon material recovered from kthe bomb hadA the following analysis.

Lower-boiling Trace CsHa Per cent by weight...` V2.7 -C4Hio dO 4-.6

n-C4H1n d0 3.0 i-CsHiz f do 10.5 n-C5H12 do 76.6 06H14 l dn 1.7 Higher-boiling do 0.9

y ,y Y 100.0

VExample IX l To arsteel bomb were charged 165.0 grams of concentrated hydrofluoricacidand 74.4 grams Yof normal butano, the bomb being agitated by a platformV shaker. The bomb VIwas heated from 145 F..up toV 302 F.; in"1 l"1our,iand,maintainedv at 302 F. for vv2 hours. After.this,Y theboinb was? cooled to !F.fin 15 minutesz: YThe hydroczar-'YV 1i* bon material recovered had the following composition. Per cent It Will 'be understood that Various parts Of the eflluent from theprocess may -be recycled. For example', any ofthe fractions obtained from fractionator 46, preferably the light-isoparafn fraction boiling below the motor-fuel range, may be advantageously recycled to coil I3 and/ or reactor 23 by means not shown that can be readily supplied by those skilled in the art; thereby the yield of hydrocarbons of adesired boiling range or of a desired carbon-skeleton structure is increased.

It valsowill -be understood that the equipment used for this process may be of corrosion-resistant steels, Monel metal, nickel alloys, aluminum and/or magnesium alloys, copper, copper alloys, orthe like, Since hydroluoric Yacid is relatively inert to metals in the absence of moisture, corrosion may be minimized by using substantially completely anhydrous hydrouoric acid and by drying `the hydrocarbon material fed to the process.-`

My invention provides a new catalytic process for reconstructing hydrocarbon materials. It provides a new process for improving the antiknock characteristicsnand the degree of saturation of motor-fuel hydrocarbons, It further provides a novel process for producing lhydrocarbons of higher and/or lower molecular weight than that of the original material. Still further, it provides a process wherein normal and slightly branched aliphatic hydrocarbons may be converted t relatively highly branched aliphatic hydrocarbons.

My process is especially advantageously applicable' to treatment of all hydrocarbon materials which comprise predominantly saturated hydrocarbons having four or more carbon atoms per molecule. Because of the variety of materials and the plurality of vpurposes to which my invention is applicable, there are a large number of modifications and variations of my invention, of which only a very few are specifically described in this specication. Additional equipment such as pumps, valves, coolers, fractionators or the like, such as are well-known to those skilled in the art, may be used in my process wherever needed or convenient. It is not intended that mention herein of specific apparatus, materials, conditions, theories, reactions, or purposes should unnecessarily limit the scope of my invention.

What I claim is:

l. A process of isomerizing a normal parain having at least four carbon atoms per molecule, which comprises subjecting said normal paran to the catalytic action of 0.2 to 4 times by Weight of Vconcentrated hydroiiuoric acid as the effective catalyst at an elevated temperature in the range of about 50 to 1000? F. for a time Suicient to effect a substantial extent of isomerization of said normal paraiiin. v

- 2.l The process of olai l, in which .said normal paraflin isnormal butane.

3. A process for improving the antiknock characteristics of a saturated hydrocarbon material boiling in the motor fuelrange which comprisesv subjecting such a hydrocarbonmaterial to reac-Vr 12 i tion in the liquid-phase-while intimately mixed with 0.2 to 4 times by weight of conezentratedr liquid hydroiiucri'c acid as the eiTecti-ve vcatalyst at a reaction temperature ofvat `least-59" F. for a time sufficient to effect alteration of the structure of saturated hydrocarbons present tol form other saturatedY hydrocarbons, and subsequently recovering from eiiluents of said treatment satu-V rated 'hydrocarbons' boilingin-the motorfuel range so produced.j v

` 4. A process of `converting a saturated hydro-- carbon material of" at least four carbon* atoms per molecule into other saturated hydrocarbons, which comprises subjecting such a materialto reaction at an elevated temperature and pressure while Vintimately mixed with 0.2'to-4 times by weight of concentrated hydroiluoric acidasthe effective catalyst for a time such as to eiTect a material alteration in the structure of saturated hydrocarbons in said hydrocarbon material into other saturated hydrocarbons, passing eiiluents of said treatment to a separating Zone wherein a hydrocarbon phase is separated from a liquid hydrofluoric acid phase, subjecting said hydrocarbon phase to fractional distillation to remove residual amounts of hydrofluoric acid contained in said hydrocarbon phase, and recovering from remaining hydrocarbons a fraction containing saturated hydrocarbons of atleast four carbon atoms per molecule and of altered structure Vs0 produced.

5. A process of converting a saturated hydrocarbon material of at least four carbon atoms per molecule, which comprises subjecting such a material to reaction at an elevated temperature and pressure whileintimately mixed with 0.2 to 4,

times by weight of concentrated hydroiluoric acid as the effective catalyst for a time such as to effect a material` alteration in the structure of saturated hydrocarbons in said hydrocarbon material, passing effluents of said treatment to a separating Zone wherein a hydrocarbon phase is separated from a liquid hydroiluoric acid phase, subjecting said hydrocarbon phase to fractional distillation to remove residual amounts of hydrofluoric acid contained in said hydrocarbon phase, separating low-boilingk material so ,removed into a hydrocarbon phase and a hydrouoric acid phase, returning said hydrofluoric acid to said reaction, returning said hydrocarbon phase to said distillation, removing as a high boiling product of said distillation a hydrocarbon material essentially free of hydroluoric acid but containing minor amounts of organic iluorine compounds, passing said hydrocarbon material to the action of granular bauxite to remove said organic fluorine compounds and. to. produce a substantially liuorine-free eiiluent, and recovering from the hydrocarbon material so purified a normally liquid hydrocarbon .fraction boiling in the: motor-fuel range. l

6. AY processY for converting hydrocarbons by reactions -comprising isomerization and disproportionation,A which comprises subjecting a normally liquid parain hydrocarbon to a reaction temperature in the presence and intimately admiXed with 0.2 to 4 times by weight of liquid concentrated hydroluoric acid as the sole catalyst `for a time suicient to convert saidparafn hyportionation, which comprises subjecting a normally liquid parafln hydrocarbon to a reaction temperature in the presence and intimately admixed with 0.2 to 4 times by Weight of liquid concentrated hydrofluoric acid as the effective catalyst for a time suii'icient to convert said'parafjn hydrocarbon in part to isomeric paraffin hydrocarbons of the same molecular Weight and in part to parans of higher and of lower molecular Weights.

8. A process for converting saturated hydrocarbons contained in a saturated hydrocarbon material by reactions comprising isomerization and disproportionation, which comprises subjecting a saturated hydrocarbon material to the catalytic action of 0.2 to 4 times by Weight of intimately admixed liquid concentrated hydrofluoric acid as the effective catalyst at a conversion tem-4 Version temperature in the presence vof 0.2 to 4 y times lby-Weight of intimately admixed concentrated liquid hydrouoric acid as the sole catalytic material for a time sufficient to elect a con-Y version of saturated hydrocarbons into other 'saturated hydrocarbons including at least one isomer of a saturated hydrocarbon so converted.

10. A process for converting a paraffin hydrocarbon contained in a saturated hydrocarbon material, -Which comprises subjecting a liquidsaturated hydrocarbon material containing at least one paraffin hydrocarbon of atleast four carbon atoms per molecule to a conversion temperature in the presence of 0.2 to 4 times by weight of intimately admixed liquid concentrated hydrofluoric acid as the essential catalyst for a time sufficient to convert said parain hydrocarbon into an isomeric parafn hydrocarbon.

11. A process for converting normal pentane into isobutane, isopentane, and isohexanes, which comprises subjecting liquid normal pentane at a conversion temperature to the catalytic action of liquid hydrogen fluoride as the essential catalyst for a time sufficient to effect ra substantial conversion of normal pentane to isobutane, isopentane and isohexane, and subsequently recovering from eiuents of said conversion a fraction comprising at least one of said isoparaflins so produced.

12. |A process for effecting disproportionation of a paraffin hydrocarbon having at least ve carbon atoms per molecule, which comprises subjecting a liquid saturated hydrocarbon material comprising such a paraffin hydrocarbon at a reaction temperature to the catalytic action of 0.2 to 4 times by weight of intimately admixed liquid hydrofluoric acid as the essential catalytic material for a time sufficient to eiect a substantial disproportionation of said parain hydrocarbon,

forming paraffin hydrocarbons having fewer and morecarbon atoms per molecule, and subsequently recovering from eilluents of said reaction a fraction comprising at least one of said paraffin hydrocarbons so produced. i

l 13. A process for isomerizingl normal pentane to produce isopentane, which comprises subjecting normal pentane to isomerization under isomerization conditions in the presence of liquid concentrated hydrofluoric acid as the essential isomerization catalyst to form isopentane, and

recovering from eiiiuents of said isomerization isopentane so produced. f

14. A process for isomerizing a saturated hy- `drocarloon having at least four carbon atoms per molecule, which comprises subjecting such a saturated hydrocarbon to isomerization under isomerization conditions in the presence of 0.2 to 4 times by weight of intimatelyadmixed liquid concentrated hydrofluoric acid as the essential isomerization catalyst to form a saturated hydrocarbon isomeric with the rst said saturated hydrocarbon, and recovering from eiliuents of said isomerization a saturated hydrocarbon fraction comprising said isomeric saturated hydrocarbon so produced.

l5. A process of isomerizing a paraiin having at least four carbon atoms per molecule, which comprises subjecting said paraiiin to the catalytic action of 0.2 to 4 times by weight of concentrated hydroluoric acid as the effective catalyst at an elevated temperature in the range of about 50 to 1000 F. for a time sufficient to effect a substantial extent of isomerization of said paraffin.

16. A process of isomerizing a saturated hydrocarbon having at least four carbon atoms per molecule, which comprises subjecting said satuf rated hydrocarbon to the catalytic action of 0.2 to 4 times by Weight .of concentrated Vhydroiluoric acid as the eifective catalyst at an elevated temperature in the range of about 50 to 1000a F. for a time sulcient to effect a substantial extent of isomerizationV of said saturated hydrocarbon.

17. A process of isomerizing a cycloparaflin hydrocarbon having at leastsix carbon atoms per molecule, which comprises subjecting said cycloparaffin hydrocarbon to the catalytic action of 0.2 to 4 times by weight of concentrated hydrouoric acid as the effective catalyst at an elevated temperature in the range of about 50 to about 1000o F, for a time sufcientto eiect Ia substantial extent of isomerization of said cycloparaiin hydrocarbon.

18. A process for isomerizing a cycloparain hydrocarbon having at least six carbon atoms per molecule, which comprises subjecting such a cycloparaln hydrocarbon to isomerization under isomerization conditions in the presence of 0.2 to 4 times by Weight of intimately admixed liquid concentrated hydrouorie acid as the essential isomerization catalyst to form a cycloparafn hydrocarbon isomeric with the rst said cycloparain hydrocarbon, and recovering from eillu- `ents of said isomerization a hydrocarbon fraction comprising said isomeric cycloparaflin hydrocarbon so produced.

FREDERICK E. FREY. 

